1. Field of the Invention
This invention relates to curable thiol/ene compositions wherein the -ene component is a multifunctional styryloxy monomer.
2. Description of Related Art
Numerous proposals have been made for curable compositions based on thiol/ene polymer systems, the essential components of which are a multifunctional alkene and a multifunctional thiol. Representative groups of thiol/ene polymers are described in U.S. Pat. No. 3,661,744 Kehr et al assigned to W. R. Grace & Co; and U.S. Pat. No. 4,008,341 Kehr, also assigned to W. R. Grace & Co; and U.S. Pat. No. 4,119,617 Hanyuda et al assigned to Showa Highpolymer Co. Ltd.
U.S. Pat. No. 4,308,367 Green et al assigned to Ciba-Geigy Corporation discloses polymerisable compositions of the thiol/ene type in which the -ene component is a compound containing in the same molecule at least one phenolic hydroxyl group and at least two groups chosen from allyl, methallyl and 1-propenyl groups. However, the phenolic hydroxyl group, being a free-radical scavenger, tends to decelerate the polymerisation reaction.
U.S. Pat. No. 4,145,479 Adams et al assigned to Armstrong Cork Company discloses a curable composition comprising at least one unsaturated polyaryoxyphosphazene, at least on aryloxy cyclotriphosphazene and a thiol crosslinking agent. Among the terminal groups suggested for the unsaturated phosphazene components are various styryloxy groups. However these compounds must have the phosphazene backbone structure, which is linked to the oxygen of the styryloxy terminal groups by a P-O- linkage, and the compounds are therefore distinct from those used in the present invention.
U.S. Pat. No. 4,543,397 Woods et al assigned to Loctite (Ireland) Limited discloses polyfunctional cationically polymerizable styryloxy compounds of the formula ##STR4## wherein R.sup.1 and R.sup.2 are H, or one of R.sup.1 and R.sup.2 are H and the other is methyl; R.sup.3 and R.sup.4 are H, lower alkyl, or alkoxy if R.sup.2 is not methyl; R.sup.5 is a divalent hydrocarbon radical; G is any multivalent organic or inorganic radical free of amino, aliphatic hydroxyl, aliphatic thiol or other groups which interfere with cationic polymerization; and n is an integer of two or more.